A next-generation mobile communication system requires a technology to break from a conventional art limited mainly to a voice service and low-speed data service and to provide a variety of high-speed multimedia services with a high-speed data transmission rate. Various technologies such as broadband frequency use and a method using a multi-antenna have been studied to achieve the high-speed data transmission rate. A system using a multi-antenna is sensitive to a feature of a radio channel in comparison with a single-antenna system in a conventional art. Accordingly, when designing a multi-antenna system, accurately ascertaining the features of a radio channel is extremely important. A next-generation radio communication system using the above-described multi-antenna is expected to be generally used in a city where electric waves are affected by buildings, trees, and the like. Also, a next-generation radio communication system using the above-described multi-antenna is expected to be widely used for radio high-speed data transmission indoors.
In general, a multi-antenna radio channel measurement system, referred to as a Channel Sounder in a conventional art, is simplex measurement system, and is divided into a transmission system and a receiving system. A simplex Channel Sounder in a conventional art measures a radio channel in a place, such as an urban macro or a city like urban micro, and an area where traffic is complex, while moving through a specific route using a moving vehicle. In this instance, to measure a radio channel, multi-antennas for transmission and transmission system are installed in a base station or steel tower relatively higher than surrounding buildings, and multi-antennas for receiving and receiving system are installed in the moving vehicle. Through the measurement method described above, a radio channel emitted in a base station, that is, a change of radio channel in various environments according to a route of a moving vehicle based on a downlink is measured. As opposed to the configuration above, a receiving system and multi-antennas for receiving may be installed in a base station, and a transmission system and multi-antennas for transmission may be installed in a moving vehicle. Through this, a moving vehicle emits an electric wave for measurement while moving through a specific route and a base station collects data of radio channel emitted by a moving vehicle based on an uplink.
However, a simplex radio channel measurement system and method of operating the same in a conventional is required to sequentially operate a downlink and uplink in order to measure the same measurement area, a variety of environments, and a number of routes. For this, a measurement apparatus and antenna are required to be installed in a base station and moving vehicle, respectively, and a downlink measurement is to be performed. After the downlink measurement is complete, the measurement apparatus and antenna of each of the base station and moving vehicle are changed and installed, and an uplink measurement is to be performed. A single measurement path in the same area and environment is measured twice in the system and method described above, which is inefficient and time-consuming and wastes a cost and human resources.
Also, features of radio channel to be measured are frequently changed depending on an environment. In particular, a speed of moving vehicle when measuring an uplink channel is not identical to a speed of moving vehicle when measuring a downlink channel, and thus those channels may not be measured in the same environment. Also, radio channel measurement data of each of the uplink and downlink measured as described above is not measured at the same time, at the same measurement point, and in the same surrounding environment, although a measurement path is the same. Accordingly, it may not be an accurate channel collection data to estimate correlation between data of each of the uplink and downlink.
Thus, a two-way radio channel measurement system is to be established, and a method and system to simultaneously measure an uplink and downlink in a same environment and condition when measuring a radio channel is required. Also, a technical control method and operation method to embody the two-way radio channel measurement system is required.